Large commercial printers often produce books (i.e., collated sets of printed signatures) on a publication-by-publication basis, i.e., the publications are produced one at a time without co-production of books of different publications. Often, a press run of a single publication is large enough to allow the printer to take advantage of postal discounts, which are generally available when certain specified counts or numbers of books are to be mailed to a particular carrier route or are to be sent to a particular sectional center facility (SCF), bulk mail center (BMC) or other postal facility.
Production processes and apparatus have been developed to permit books of diverse publications to be collected in a presorted sequence to allow greater postal discounts to be taken than would otherwise be available if the publications were not collectively presorted. For example, Mayer et al. U.S. Pat. No. 5,287,976 discloses a system for co-mailing the books of diverse publications including a co-mailing line which accepts preproduced and preaddressed books and which deposits the books in a sequence on a conveyor so that the books can be bundled in a fashion to obtain significant postal savings. While such a system can accomplish co-mailing, the system is by necessity complex. Also, in the event that one or more books are damaged or defectively produced during the collection process, there is only limited opportunity to economically replace the book with a different book and still obtain the desired postal discount. Further, the high cost and operation expense of the co-mailing system render it economical only under limited circumstances.
It would also be possible to co-produce diverse publications on a single conventional binding line so that the books are produced initially in the desired postal sequence. However, this would require the use of a large number of packer boxes to hold the required signatures, and quickly becomes impractical owing to the relatively large space required for and the downtime associated with the many packer boxes.